Electric clock



March 17, 15%;1. J. E. BROBST 1,797,044

ELECTRIC CLOCK Filed March 15, 1929 IT1\/HJCOT*: John E. BFObSt. by Z. GYM/4M His Attorn ey.

Patented Mar. 17, 1931 UNITED STATES PATENT OFFICE;

JOHN BROBST, OF-SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC CDM- PANY, A CORPORATION OF NEW YORK ELECTRIC CLOCK Application filed March 15, 1928. Serial No. 347,374.

My invention relates to an electricall operated timing device such as may be emp oyed as a clock or impulse timer and its object is to provide a simple, rugged and accurate device of this character the operation of which is independent of the voltage of the source of supply and one which may be energized by direct or alternating current.

In carrying my invention into effect I provide automatic means responsive to the oscillations of the pendulum for shifting the center of gravity of the pendulum at the extremities of its oscillation in a manner and to the extent necessary to supply oscillation impulses to the pendulum and maintain it in oseillation.

The features of my invention which are believed to be novel and patcntable will be pointed out in the claims appended hereto. For a better understanding of my invention reference is made in the following description to the accompanying drawing which shows the operating features of one form of the device as used to drive clock hands and to operate an impulse relay.

Referring to the drawing we may consider it to re resent a back view of the essential parts of a clock mechanism built in accordance with my invention. A pendulum with an adjustable weight 10 is suspended at 11. Between the weight 10 and pivot point 11 the pendulum carries an electromagnetic motor device for supplying the necessary impulses for keeping the pendulum in operation. .A magnetic framework 12 is provided with two coils 13 and 14 and a movable magnetic armature 15 pivoted at 16 on the center line of the pendulum. The armature carries an adjustable weight 17. Above the motor on the pendulum is a support carr ing electrical spring contacts 18 and 19. T ese contacts cooperate with adjustable stationary contacts 20 and 21 mounted on a stationary portion of the clock structure. A source of supply indicated at 22 is connected between contacts 20 and 21 and the pivot point of the pendulum.

The pendulum stafi is made of conducting material and suitably insulated from all of the contacts. Coil 13 is connected between contact 19 and the magnetic framework 12 so that when the pendulum swings to the left and contact is made between 19 and 21 current flows from source 22, through contacts 21 and 19, through coil 18, framework 12, enduluni pivot 11, back to the source. hen

' the pendulum swings to the right, contacts 18 and 20 are closed and coil 14 is energized.

All of the parts carried by the pendulum with the exception of armature 15 and its counterweight 17 are preferably balanced with respect to the center line of the pendulum so that if the position of armature 15 was centered, the center of gravity of the pendulum would fall on a line passing through the pivot point 11 and pivot 16. The position of armature i5 is shifted near the ends of the normal swing of the pendulum, thus shifting the center of gravity of the pendulum from one side of the center line to the other to provide the impulses for keeping the pendulum in oscillation and the electromagnets are employed to move the armature in the proper sequence to accomplish this result. Thus, to start the pendulum into operation, it is swung to the right sufficiently to make contact between 18 and 20. This energizes coil 14 and the armature 15 is attracted and rotated about pivot 16 to the dotted line position represented in the drawing. Shortly thereafter the pendulum swings to the left and near the end of its extreme left oscillation contact is made between 19 and 21. Coil 13 is energized and the armature returned to the full line position shown in the drawing. Thus, at the extremities of its oscillation the center of gravity of the pendulum is shifted a slight amount in a direction away from a vertical axis passing the point of suspension and corresponding amounts of potential energy are added to the pendulum, which amounts are made sufficient to supply the friction losses of the pendulum and as much additional energy as is desirable for the pendulum to operate a'ratchet device, for example, for driving a clock at a constant rate. c

The rate of the pendulum may be accurately adjusted in the usual manner by adjusting the position of weight 10 up and down.

The amount of energy supplied by the im-- pulse motor may be varied by adjusting the position of weight 17. The pendulum may drive a clockwork repr sented at 23 through the action of a pawl 24 pivoted to the pendulum and operating on a ratchet wheel 25. In addition. the impulses from the source :22 may be carried through a relay as at 26 to supply timed impulses to other electrical devices such as secondary clocks, not shown. The operation of the magnetic motor mounted on the pendulum and the rate of the peu dulum is independent of voltage changes in the source of supply so long as it is suflicient to cause the armature 15 to shift in the manner described. The source may be either diroot or alternating current.

It will be apparent also that the size and general arrangement of the parts may be varied to suit the character of the installation without departing from the invention and in claiming my invention I intend to include all arrangements falling within the true spirit and scope thereof.

\Vhat I claim as new and desire to secure by Letters Patent of the United States is:

l. A timing device comprising a pendulum, and means responsive to the oscillations of said pendulum for shifting its center of gravity relative to its point of suspension in a manner to supply the required oscillation impulses to maintain the pendu lum in oscillation.

2. A timing device comprising a pendulum, means for supplying oscillation impulses to said pendulum to maintain it in operation comprising means for automatically shifting the center of gravity of the pendu lum at the extremities of its oscillations.

-3. A timing device'comprising a pendulum, means for supplying oscillation impulses to said pendulum to maintain it in operation comprising means for automatically shifting its center of gravity away from the vertical axis through its point of suspension at the extremities of its oscillations.

'4. A timing device comprising a pendulum, a movable weight on said pendulum, and motor means responsive to the oscillations of said pendulum for moving said weight with respect to the pendulum to supply energy for maintaining the pendulum in oscillation.

5. A timing device comprising a pendulum. a Weight movable on said pendulum to supply oscillation impulses thereto, motor means on said pendulum for moving said weight, and means responsive to the oscillations of said pendulum for controlling said motor.

6. A timing device comprising a pendulum, a weight movable on said pendulum to supply oscillation impulses thereto, electric motormeans on said pendulum for moving said weight, and electric contacts actuated by said pendulum due to its oscillations for controlling said motor.

7. A timing device comprising a pendulum, an electrically actuated motor entirely mounted on said pendulum and controlled by the oscillations of said pendulum for maintaining said pendulum in oscillation.

8. A timing device comprising a pendulum, an electromagnetic device having a movable arm-ature mounted on said pendulum, said armature comprising a weight for shifting the center of gravity of the pendulum with respect to the vertical axis of suspension at the extremities of the pendulums oscillation in a manner to supply oscillation impulses thereto and maintain the pendulum in oscillation, energizing circuits for the electromagnetic device and contacts actuated by the oscillations of said pendulum for controlling said circuits.

9. A timing device comprising a pendulum, an electromagnetic device having a movable armature and a pair of energizing coils for moving said armature in opposite directions on said pendulum, contacts actuated by the swing of the pendulum in one direction for energizing one of saidcoils, contacts actuated by the swing of the pendulum in the opposite direction for energizing the other coil, said armature comprising a weight the movement of which shifts the center of gravity of the pendulum in a manner to maintain the pendulum in oscillation.

10. A timing device comprising a pendulum. a weight pivoted on the center line of said pendulum and adapted to be rotated about such pivot in the plane of oscillation of the pendulum to shift the center of gravity of the pendulum from one side to the other of such center line, automatic means for moving said weight at the extremities of the oscillation of the pendulum in a manner to supply oscillation impulses to said pendulum and maintain it in oscillation, and means for adjusting said weight to vary the magnitude of such impulses.

In witness whereof, I have hereunto set my hand this 13th day of March, 1929.

JOHN E. BROBST. 

